The invention relates in general to pipe joints and in particular to a new and useful connecting nipple for circumferentially ribbed insulating tubes.
If the relatively thin-walled insulating tubes which, as is well known, serve the purpose of enclosing electrical cables, are to be joined to electrical equipment, a connecting nipple must be interposed having on one side a threaded connection for securing to the housing wall of the electrical equipment, and on the other side a socket for receiving the end of the insulating tube. Such nipples should establish a connection which can no longer be unlocked, except with the use of a tool and prior art construction of this kind are very expensive.
The present invention is directed to a nipple permitting interconnection of circumferentially ribbed insulating tubes by simple manipulation and without a tool, while making a disconnection of the nipple from the tube impossible without the use of a suitable tool.
For this purpose, the invention provides in a nipple comprising an inwardly shouldered piece of pipe having a threaded connecting portion and a receiving socket portion, that has a projection member engageable in a groove or recess of a tube to be connected and which is held engaged until separated by a tool. The locking element, made of a plastic, as is the piece of pipe, may be designed as a pushbutton or a spring arm which can be pushed radially inwardly into a flush or sunken effective position. Slides tangentially engageable into corresponding holes of the socket portion may also be provided as locking elements.
Accordingly it is an object of the invention to provide a connecting nipple for engagement with a tubular member which includes means for locking the connecting nipples to the tubular member and a lock element which when engaged must be forceably disengaged, for example by a tool.
A further object of the invention is to provide a connecting nipple which is simple in design, rugged in construction and economical to manufacture.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.